The leader of Spain's debt-ridden northeastern region of Catalonia all but conceded Thursday he will not hold a promised 2014 poll asserting the right to self-determination if Madrid maintains its fierce opposition.

Catalan president Artur Mas made the statement less than a week ahead of the region's September 11th national day, when separatists will attempt to form a human chain of hundreds of thousands of people across Catalonia to call for breaking away from the rest of Spain.

Mas said the referendum he has promised for next year, despite outright opposition from Madrid, would be held legally and in agreement with the Spanish government.

"I think the Spanish government will tend more to obstruct the whole process," however, he admitted in an interview with Catalan public radio.

If Madrid blocked his promised poll in 2014, as expected, then the region would transform the 2016 Catalan government elections into a kind of plebiscite on the right of Catalonia to decide its own future, Mas warned.

"If the Spanish government flatly refuses to accept any path of political agreement and shelters under supposed legality so that legality becomes a brake to the popular will, we will always have a final framework that will be legal, which will be the elections," he said.

A vote for parties favouring self-determination in the 2016 Catalan elections, however, would not have any legal impact on the region's constitutional status.

Proud of their distinct language and culture and their business savvy, yet suffering in Spain's economic crisis, many Catalans resent seeing their taxes redistributed to other regions of the country.

As a result, separatist stirrings have surged in the region, home to 7.5 million people and a major source of exports for recession-struck Spain.

Spanish Prime Minister Mariano Rajoy's right-leaning government has already asked the Constitutional Court to strike down a Catalan parliamentary declaration in January 2013 asserting sovereignty. The court agreed in May to hear the case, meaning the declaration was suspended awaiting a ruling.